Hitachi RWM-(H)FSN3E, Service Manual

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3 Piping work and
refrigerant charge
SMGB0070 rev.1 - 08/2011
67
3
3.2 Water pipe work and connection
3.2.1 General notes
• Install the factory supplied Shutdown Valves for connecting the Water Inlet / Outlet pipes as close as possible to the
Indoor Unit, in order to minimise flow resistance and, if necessary, for water flow regulation.
• It is advisable to use flexible joints after the Shutdown Valve for the water Inlet / Outlet piping to prevent the transmis -
sion of vibrations.
• Proper Water pipe inspection should be performed after piping work to assure there is no water leakage in the circuit.
Fill in the water circuit (refer to Circuit Water Filling-in chapter) and open inlet and outlet Shutdown Valves.
• The Indoor Unit is equipped with an air purger (factory supplied) at the highest location of the Indoor Unit (Electric
Heater top). If this location is not the highest of the water installation, air might be trapped inside the water pipes, which
could cause system malfunction. In that case additional air purgers are provided (field supplied) to ensure no air enters
the water circuit.
• It is advisable to insulate the water pipes, joints and connection in order to avoid heat loss.
•
When the unit is stopped during shutdown periods and the ambient temperature is very low, the water in the pipes and
the circulating pump may freeze, thus damaging the pipes and the water pump. In order to prevent this, the unit has a
self-protection mechanism which should be activated (refer to
Available optional functions
chapter).
C A U T I O N
When connecting the water piping to the indoor unit, it is necessary to install 500mm of flexible water piping
from the indoor unit, in order to avoid metal expansion problems due to temperature. After these 500mm install
copper Piping.
N O T E
The maximum piping length depends on the maximum pressure availability in the water outlet pipe. Please
check the pump curves.